Red blood cells transport oxygen and eliminate carbon dioxide generated by metabolism in peripheral tissues, both of which rely on gas exchange via type I alveoli (ATI).11 Among our findings, the ferroxidase ceruloplasmin (CP), which is involved in the peroxidation of Fe (II) transferrin to Fe (III) transferrin, was significantly upregulated in the COVID-19 lung tissue (Fig. 1c). Here, CP is linked to COVID-19.